A new study suggests that a metric called "sleep age" can predict health disturbances and a person's lifespan.
Stanford University School of Medicine researchers analyzed about 12,000 studies, focusing on an individual reporting their sleep characteristics, such as chin and leg movement, breathing, and heartbeat.
In the study published in npj Digital Medicine, researchers used polysomnography tests (PSGs) to develop a system that predicts a person's sleep age, which they define as "a projected age that correlates to one's health based on their quality of sleep."
This system, using machine learning, then identifies the sleep variations most closely linked to mortality.
"Our main finding was that sleep fragmentation -- when people wake up multiple times throughout the night for less than a minute without remembering it -- was the strongest predictor of mortality," says study author Emmanuel Mignot, MD, PhD from Stanford Medicine.
People whose sleep age looks much older than their actual age may be at increased risk of mortality "based on the sleep of patients who later died." Researchers also estimated that a ten-year change in sleep age could decrease or expand life expectancy to 8.7 years.
According to the researchers, changes in heart rate and breathing during sleep may indicate a health disturbance, as sleep disruption is one of the first symptoms of many disorders. For example, violently acting out dreams might predict Parkison's disease five to ten years before other symptoms appear.
However, Mignot notes that older sleep age does not necessarily determine a higher mortality risk, as "there is always huge natural variation."
Poor sleep is linked to numerous chronic diseases and conditions, such as type 2 diabetes, cardiovascular disease, obesity, and depression. In addition, a recent study from the University of California, Berkeley, suggests that lack of sleep makes us less willing to help others.
Another study from the same research group demonstrates that sleep-deprived people are less inclined to engage with others and are seen as more "socially repulsive."
Improving sleep quality
The National Sleep Foundation (NSF), a non-profit organization, offers tips on improving your sleep.
- During the day, spend time in bright light, such as natural light or equivalent brightness.
- Exercise regularly — aim for 30 minutes a day, five days a week.
- Eat meals at consistent times every day.
- Avoid heavy meals, nicotine, caffeine, and alcohol before bedtime.
- Use a consistent routine with a relaxing wind-down before going to bed.
- Put your devices away an hour before bed and sleep in a quiet, cool, and dark environment.
npj Digital Medicine. Age estimation from sleep studies using deep learning predicts life expectancy.
Stanford University School of Medicine. Scientists use ‘sleep age’ to infer longterm health.
National Sleep Foundation. Be Your Best Slept Self.